1. Field of Invention
The present invention relates to an apparatus for controlling liquid-crystal-display (LCD) shutter glasses and, more particularly, to an apparatus capable of alternately making the right and left LCD-type shutter of the LCD shutter glasses transparent. An observer who wears the LCD shutter glasses controlled by said controlling apparatus will feel the three-dimension effect if the alternately transparent speed of the right and left LCD-type shutter is matched with the vertical synchronization signal.
2. Description of Prior Art
In keeping with the improvement of computer technology, the computer software industry has also shown incredible advances through the aid of high-speed computer hardware. For example, computer software combining three-dimensional pictures with stereo-sound has bloomed, whereas two-dimensional pictures were combined with mono-sound in the past. More particularly, it is popular for an observer to enjoy the truly three-dimensional pictures or images by wearing a pair of LCD shutter glasses including a right and a left LCD-type shutters.
In order to produce the three-dimensional effect for consumers, the linear perspective method or the binocular disparity method is usually adopted to induce depth perception, then the vision nerves will produce the three-dimensional effect by the depth perception. The said linear perspective method utilizes the length and difference of several lines to express the three-dimensional effect, as shown in FIG. 1. FIG. 1 illustrates the frontal view of a pair of parallel tracks by the linear perspective method. The terminals of the tracks far away from the observer will be merged together from the view of observer. On the other hand, the distance between two tracks will increase if the tracks are closer to the observer. That is, for the purpose of producing three-dimensional effect by the linear perspective method, the distance between two parallel lines should be decreased if the those lines are far away from the observer, and the distance between two parallel lines should be increased if those lines are close to the observer. Many computer software programs usually adopt the linear perspective method to produce three-dimensional pictures, but those three-dimensional pictures drawn by this method are not truly xe2x80x9cthree-dimensionalxe2x80x9d. Those pictures are different from three-dimensional objects of the real world and could only be shown in the two-dimension plane, such as screens or displays.
The other method of producing the three-dimensional effect is the binocular disparity method. When the observer looks at an object of the real world, the image forming on the retina of the left eye and the image forming on the retina of right eye are different from each other because the different lines of vision. The farther the distance between the object and the observer, the greater the difference between those two images. According to the above-mentioned description, if the image forming on the retina of the left eye and the image forming on the retina of right eye are different from each other, a truly xe2x80x9cthree-dimensionalxe2x80x9d picture could be created because of the depth perception. The prior art of xe2x80x9ccomputerized stereoscopic image system and method of using two-dimensional image for providing a view having visual depthxe2x80x9d issued by U.S. Pat. No. 5,796,373 utilizes one pair of LCD shutter glasses and the binocular disparity method to produce a three-dimensional effect. In that prior art, the alternately transparent rate of the right and left LCD-type shutters is synchronal with the alternate emerging rate of the right and left images shown in the computer screen. That is, when the left image for the left eye is shown on the screen, the left LCD-type shutter is transparent and the right one is opaque. On the other hand, when the right image for the right eye is shown on the screen, the right LCD-type shutter is transparent and the left one is opaque. If the alternate emerging rate of the left and right images is less than the delay time of the vision, a truly three-dimensional picture will be created.
In that prior art, the 3-D image system comprises a controlling device, as shown in FIG. 2(a). The controlling device mainly comprises a power means, a VGA interface buffer, a shutter switch means, a shutter controlling means, and a output means. There are several drawbacks in the controlling device. First, because the controlling device is separate from the computer, it can not use the power supply of the computer and must have the power means to offer the electric power. The function of the power means is to transduce the external AC power into the DC power in order to provide the stable electric power for the other circuits of the controlling device. The power means will complicate the circuits of the controlling device and interfere with the stability of the other circuits in the controlling device.
Secondly, because of the separation of the controlling device from the computer, the controlling device will be combined with the LCD shutter glasses, as shown in FIG. 2(b). It will be inconvenient and uncomfortable to wear the LCD shutter glasses with the extra controlling device. Thirdly, the controlling device of the prior art must receive the horizontal synchronization signal generated by the VGA card in order to lock and detect the positive or negative value of the vertical synchronization signal. The controlling device then requires the said shutter switch means to execute the function of locking and detecting. The requirement of said shutter switch means will complicate the circuit of the controlling device and increase the cost. Fourthly, in order to distinguish the driving signal of the left LCD-type shutter from that of the right LCD-type shutter, it is required to add the output means in the controlling device. The output means comprises an alternate switch to swap the shutter driving signal to the left or right LCD-type shutter of the said LCD shutter glasses. The extra circuit of the output means will also complicate the circuit of the controlling device and increase costs.
In view of the explanation above, an ideal controlling apparatus of LCD shutter glasses should meet the following requirements:
(1) To exclude the power supply circuit, that is, to exclude the said power means in the prior art, in order to avoid the complication of the circuit design and to minimize the interference of the other circuit in the said controlling device.
(2) To separate the said controlling apparatus from the LCD shutter glasses in order to diminish the burden of wearing the LCD shutter glasses.
(3) Only to receive the vertical synchronization signal, not the horizontal synchronization signal, from the VGA card to reduce the complication of the said controlling device and to reduce the cost.
(4) To output the driving signals of the left and the right LCD-type shutters of the said LCD shutter glasses without the help of the said alternate switch swapping the said driving signal to the left or right LCD-type shutter.
The present invention relates to an apparatus for controlling liquid-crystal-display (LCD) shutter glasses (hereinafter, a viewing apparatus) and, more particularly, an apparatus capable of alternately making the right and left shutters of the said viewing apparatus transparent. In other words, when the image for the left eye is shown on the screen, the left LCD-type shutter of the said viewing apparatus is transparent and the right LCD-type shutter is opaque. On the other hand, when the image for the right eye is shown on the screen, the right LCD-type shutter is transparent and the left one is opaque. The driving signals of the left and the right LCD-type shutters of the said viewing apparatus are controlled by the vertical synchronization signal generated from the VGA card in a computer. By means of the alternate transparency of the left and right shutters, a truly three-dimensional effect will be produced by the binocular disparity method.